When the reactor blew, the world's fabric turned inside-out. Some things will never be the same.

— Researcher

The Thaumanova Reactor is a ruined asuran city in northwest Metrica Province. The complex was destroyed recently in an Inquest experiment gone awry, when they were studying draconic energies (inaccurately believed to be more chaos magic by the Inquest) when the facility was designed to study actual chaos magic. The resulting explosion tore the fabric of reality, an attribute of chaos magic, and created chaos rifts teleporting creatures from across Tyria of the surrounding areas.

Unintentionally, the experiment helped the Inquest and their consultant identify the network of magical channels that criss-cross the globe known as ley lines. The city itself was built on an intersection of these channels, causing the disaster. After the explosion, the energy source that the Inquest was experimenting on was moved to the Thaumacore Inquiry Center in Toxal Bog, causing the chaos effect to spread northward. The effects of the underground experiment also affected other areas such as Chaos Crystal Cavern in Iron Marches.

The site of the disaster is considered extremely dangerous, as it is full of chaotic materials and waste, on top of the aforementioned creatures teleported in at random. Additionally, the disaster seems to have divided the area up into five distinct sections, four of which hold ties to the elements of fire, ice, water, and vegetation - as well as a nearby cavern holding a Branded-looking crystal.

Some of the crystals used in the creation of the experiment come from the Chaos Crystal Cavern in the Iron Marches. After the disaster, the remaining crystals at the excavation site began exhibiting a "twinning" effect, attracting chaos rifts to that region.